(1) Field of the Invention
The invention is related to a raceway for fastening, guiding and protecting electric cable means with the features of the preamble of claim 1. The invention relates more particularly to the installation of the cabling on aircraft doors, in particular airplanes passenger doors or airplanes cargo doors.
(2) Description of Related Art
Vehicles, including automobiles, trucks, watercraft, and aircraft, have included electrical cabling for over a century. However, installation of these cables can be tedious and inefficient, due to the requirements of space, weight, and the amount of cabling required. For example, a modern airplane or ship may have more than a hundred miles of electrical wiring.
Composites, in particularly Carbon Fiber Reinforced Plastics (CFRP) are applied extensively throughout the fuselage of recently developed airplanes. This extensive use of CFRP raises problems, also relevant looking at the installation of electrical harnesses.
The document “Design guidelines: Design Guidelines for Shielding Effectiveness, Current Carrying Capability, and the Enhancement of Conductivity of Composite Materials”, NASA Contractor Report 4784, R. W. Evans, Tec-Masters, Inc.• Huntsville, Ala.; August 1997″ discloses risks of current injection into fiber reinforced composites parts (FRP) caused by damaged insulations of electric cables or cut electric cables where the routing of said cables is close to CFRP parts, leading most likely to undetected structural damages of the FRP and electric cables; e.g. loss of matrix integrity by heat induction.
The electric cable installation in doors, i.e. the electrical harness is also exposed to mechanical caused damages, among others since door areas are zones of higher risk of abusive load application. Especially for cargo doors and in cargo loading areas, abusive loads are a big issue since the electrical harnesses are well accessible and are often abused as handle bars.
Drilling holes and cut outs lead to disrupted fibers in CFRP structures. Said disrupted fibers cause losses in the strength properties of the CFRP structures and are cost increasing too, due to machining time and drilling tool deterioration. Therefore, drilling holes and cut outs for cable through routing should be avoided or at least reduced on CFRP structures, especially in areas, where the structure is highly loaded. Equally high numbers of rivets, needed for known harness fastening, destroy the carbon fibers.
Some standard parts, such as support clamps for electric cables provide for some protection against current injection but imply many drilling holes on CFRP structures and are not suited for mechanical protection. Harnesses provide for mechanical and/or electrical protection without any solution for the number of drilling holes on CFRP structures.
The document U.S. Pat. No. 3,792,189 A discloses a raceway for housing and protecting electric cable means along structural parts. The raceway comprises at least two essentially longitudinal housings each with a base wall integral with essentially parallel side walls. Said base wall and said side walls provide a cable canal open at opposed ends of each of said at least two essentially longitudinal housings. Said at least two essentially longitudinal housings are movable telescopically into one another at said open end by means of complementary male element or female element means and each of said essentially longitudinal housings is provided with at least one fixation bolt to the housing.
The document GB 200324766 A (GB 2407439 A) discloses a device providing a protective sleeve around a bundle of one or more cables and bridging gaps between raceway sections. The device comprises a substantially flat, bendable web portion, having at least one opening adjacent one edge and a guide, slidable through the at least one opening, projecting from the opposite edge. The device is preferably formed from a single component, and is formed from PTFE.
The document U.S. Pat. No. 5,271,585 discloses a fiber optics cable raceway formed of main channel members and telescope members. The main channel members have a generally U-shaped cross-section with a base, sides, and, at the top, inwardly extending lips. The telescope members have the same cross-section, but are slightly larger so they can fit about the main channel members for a longitudinally sliding fit. By alternately, interfitting main members and telescope members and adjusting the length by telescopic sliding, a raceway of the desired length can quickly be assembled. Small locking clips can then be fitted about the respective overlapping lips of two members to prevent further sliding. The raceway can be installed below the floor by the use of brackets hanging on pre-existing floor-supporting pedestals. It can be installed above a dropped ceiling by the use of hangers clamped to the grid struts of the ceiling. The locking clips serve to electrically interconnect the channel members and the telescope members.
French patent application FR 2 481 015 A1 discloses a cable raceway formed by individual elements, each made by injection and comprising a lower part, side walls and, optionally, an upper part, the individual elements being attached by means of an extension in one of the element that fits into a housing of the adjacent element.
Likewise, French patent application FR 2 680 206 A1 discloses another cable raceway formed by a plurality of elements having an U-shape cross section and being linked by the fitting of one element's extension into another element's slide channel.
Utility model DE 70 15 776 U and UK patent application GB 2 399 694 discloses yet further cable raceways in which the elements may be locked by introducing a protrusion into the next element's housing.